This invention relates to a bedding system, and more particularly, to an improved bedding mattress cover assembly for use with a mattress core for maximizing the restfulness of sleep of a person sleeping atop the mattress.
The quality of a person's sleep and the rest derived from that sleep is dependent upon the comfort of the person reclining atop a sleeping surface, such as a mattress surface. One way in which this comfort can be measured is by the number of movements a person makes over the course of a normal night's sleep. Two factors which have been shown to affect comfort on a mattress are the amounts of pressure applied by the mattress to the body and the support characteristics of the mattress. When a healthy sleeper becomes "uncomfortable", either consciously or subconsciously, they move to relieve the discomfort. This discomfort can come from excessive pressure on the body or improper support from the mattress.
During the night, a healthy person usually goes through approximately four to six sleep cycles. These sleep cycles consist of both REM and non-REM sleep. Non-REM sleep is generally divided into stages I and II, which are light sleep, and stages III and IV which are deep sleep. All levels of sleep are important, but it is during stages III and IV that we get our deepest and most restful sleep.
When a sleeper moves or undergoes a major postural shift, the sleeper arouses to a lighter level of sleep or awakens. If the event of awakening is short in duration, it is often referred to as a transient arousal. The more awakenings and transient arousals which occur in a night or a sleep cycle, the less restful the sleep. Therefore, the more discomfort a sleeper feels during the night, the more that sleeper will move and the more awakenings and transient arousals will occur which will result in less restful sleep.
A perfect mattress, or sleep surface, would eliminate all awakenings or transient arousals associated with discomfort caused by excessive pressure or improper support by the mattress. In fact, sleep studies have shown that when a person is reclining atop a mattress and mattress cover assembly made in accordance with the invention of this application, it will substantially reduce the amount of pressure exerted on the body from the mattress and provide optimum support.
In Torbet U.S. Pat. No. 4,662,012, and in U.S. Pat. No. 4,982,466, there are disclosed multiple zone, constant zone pressure, air mattresses for supporting a person in a reclining position while maintaining minimal supporting body surface pressures. To that end, the mattresses disclosed in both of the above-identified patents utilize zones of differing, but constant air pressure along the length of the mattress, with the pressures in each zone being maintained constant even with body shifts on the mattress. This is in contrast to conventional non-zoned mattresses which maintain a common and constant degree of firmness or resistance to vertical deflection over the whole surface area and for the full length of the mattress, but which change pressures in response to varying loads as a person shifts position on the mattress.
Experimentation has now shown that a mattress should be divided into at least three, and preferably four, longitudinal zones of differing firmness or resistance to vertical deflection in order for the body of a person reclining atop the mattress to be supported with minimal pressures at the high pressure points on the body when lying on either their back or side. This is achievable only when the mattress is divided into at least three, and preferably four, longitudinal zones, each having a different level of resistance to vertical deflection.
But even when a mattress is properly zoned throughout its length, there is a problem of transmitting loads of a person's weight from atop the mattress through mattress covering material to the underlying zone of the mattress core. Typically, mattresses are covered with layers of fibrous matting which are, in turn, covered with an outer layer of material commonly known in the bedding industry as "ticking". The ticking is generally applied in three sections, the sections being a top panel, a bottom panel, and side and end panels. Conventionally, the panels are sewn together on the mattress unit with the top and bottom panels being physically attached to the mattress core.
More recently, the fibrous matting material which was positioned on top of the mattress core has been replaced by unitary pads or so-called "topper pads" of resilient material such as polyurethane foam, sandwiched between quilted layers of woven fabric. Such a mattress topper pad is shown, for example, in U.S. Pat. No. 4,463,466. But whether conventional fibrous pads or topper pads are placed atop the mattress core, there is the problem of transmitting pressures and weights supported by the mattress core from the body of the person resting atop the mattress through to the core without a distortion of those pressures by the ticking or covering material.
The tendency is for the ticking to hammock when supporting a body, which causes the majority of the pressure and weight of a person atop the mattress to be supported from the hammocked ticking. The hammocked ticking creates excessive body surface pressures which cause discomfort and sleep interruptions. This excessive body surface pressure is derived from the hammocked ticking or topper pad because it is carrying a substantial portion of the body weight, and distorts the pressure that the mattress core would experience in the absence of the hammocked ticking or covering material. This pressure distortion occurs even in mattresses which are perfectly zoned, imparting excessive pressure to selected parts on a body resting atop the mattress and thereby disturbing the sleep pattern of the body,
It has therefore been an objective of this invention to provide a zoned mattress core and cover assembly which includes a covering material and which is capable of supporting a body with minimal supporting surface pressures at any point on the body.
It has been another objective of this invention to provide an improved zoned mattress core and cover assembly for supporting a person reclining atop the mattress with minimal supporting surface pressures at any point on the body,
Still another objective of this invention has been to provide an improved zoned mattress core and cover assembly for enhancing the sleep and minimizing the transient arousals of a person sleeping atop the mattress.
Still another objective of this invention has been to provide an improved mattress cover including a topper pad which increases sleeper comfort and which maintains and thereby enhances posturization of a posturized or zoned mattress core.